“So maybe this is it. First contact. The day mankind officially comes into contact with an alien race” – the Doctor

StorylineThe Doctor takes Rose home to see her mum but it’s been a year since she left and Jackie has been out of her mind with worry. Just as Rose is lamenting that no one will believe her stories of aliens, a spaceship flies overhead, smashes through Big Ben and plunges into the Thames. Earth is put on a state of emergency. Green aliens have infiltrated 10 Downing Street, zipping themselves into the skins of tubby politicians. The Slitheen family intend to trigger a nuclear cataclysm that will reduce Earth to molten slag, which they can then sell off as rocket fuel. Rose’s boyfriend Mickey and Harriet Jones MP help the Doctor thwart the Slitheen scheme, but Number Ten is destroyed in the process.

Looking back now after eight years, knowing that she’ll become prime minister in later episodes, I can’t help seeing Harriet as a prototype for Birgitte Nyborg from the superb Danish series, Borgen. That might sound like overstatement, but both form a very small club of politicians in TV drama who are hugely sympathetic, female and enjoy a rapid rise to PM.

And Wilton, for me, is a major saving grace in this flashy but silly, disappointing story. After three astonishingly impressive opening episodes, which set the bar high in 2005, Russell T Davies’s first two-parter marks the first dip in quality for his brand of Who.

My main bugbear is the Slitheen. “Doctor Who is all about big green monsters,” Davies once asserted, claiming to “love” these galumphing, bug-eyed lizards – “a creature kids will relate to because it’s big and it farts”. I can tell you that none of the kids I know rated them and for a big kid such as myself, willing to accept all sorts of nonsense, the Slitheen are patently absurd.

Reptiles climbing into a sloughed human skin may read well on paper – and could be truly horrific on screen – but the execution here is a letdown. Also, in Doctor Who terms, it’s not an original idea: Scaroth in City of Death and the Foamasi in The Leisure Hive failed for the same reason. How can these barely contained aliens possibly make human eyes and mouths work? How does a Slitheen claw fit inside a human hand?

Does anyone swallow that all this is achieved by a “compression field”? “It literally shrinks them down a bit,” explains the Doctor. “That’s why there’s all that gas. It’s a big exchange.” I’m not averse to a bit of flatulence, by any stretch, but if a monster is going to guff, at least make it comical. There are no laughs here.

The Slitheen will never work for me. It speaks volumes that the costumes were often reused in the more child-oriented The Sarah Jane Adventures and have been left to rot since Steven Moffat took over Doctor Who.

The pig-in-a-spacesuit decoy is also on the silly side, but bearably cute. At times the haste and roughness of the production show through, and I’m not always entirely convinced by Christopher Eccleston – surprising, given how highly I rate him as an actor. Maybe it’s the script’s fault; perhaps it’s a lack of direction or the fact that these episodes contain some of his earliest scenes before the cameras, but the characterisation feels forced – his gormlessness, his simpleton grin, his awkward gait. There’s a sense that Eccleston doesn’t fully understand the Time Lord.

Billie Piper fares better. Apart from Rose’s throwaway dig at the Doctor “You’re so gay” – even more horrible now than it was in 2005 – she has several genuinely touching scenes with her mum, the always superb Camille Coduri. Jackie being attacked by a policeman/Slitheen in her own kitchen is the most effective aspect of the triple-peril cliffhanger.

This new era has been criticised for being too soapy, for mining the mundanity of Rose’s background, and even the Doctor warns Rose, “Don’t you dare make this place [the Tardis] domestic.” There’s a lot of soul-baring in the Tylers’ flat and Rose’s farewells drag on for a full seven minutes after the invasion plot is wrapped up. Yet Russell T Davies has scored by making Rose, Jackie and Mickey vivid, real; he brings the perils of Doctor Who home, staging an invasion that for once everybody notices.

I can’t fault Davies’s ambition. Bold strokes include the spaceship demolishing Big Ben and plunging into the Thames (staggering effects); the BBC’s Andrew Marr reporting from Downing Street (that dates it); the brief reappearance of Unit and annihilation of their top brass; the prime minister (unnamed, nondescript) falling dead from a closet; and, ultimately, the obliteration of Number Ten – apart from an armoured cabinet room, from which the Doctor, Rose and Harriet emerge unscathed…

There are lots of little touches I’d forgotten, such as Jackie entering the Tardis and dashing out again in a tizzy to report the Doctor as an alien; the Doctor making peace with “Mickey the idiot” and inviting him to join the Tardis; Bad Wolf appearing as graffiti on the police box, presaging the season finale; and scientist Dr Sato (Naoko Mori) who, rather like The Unquiet Dead’s Gwyneth, would gain an unexpected afterlife as Toshiko in Davies’s next project, Torchwood.

So farts and hiccups, yes, but at its best the two-parter awkwardly known as Aliens of London/World War Three sows seeds for things to come – and ends on an electrifying trail to Dalek...